The Northern Red-backed Vole lives in dry tundra and northern boreal forests (taiga). Two distinct coat coloration patterns exist within the species, one darkly colored, and a paler version. The darker morph more frequently occurs in the taiga, and the paler individuals tend to inhabit the tundra. Individuals of tundra populations also tend to be larger than their taiga-inhabiting relatives, a probable adaptation to the harsher wintry conditions of the tundra, where there is less snow cover to insulate small terrestrial mammals against the cold. Breeding females maintain territories that do not overlap, but breeding male territories encompass several territories of females and non-breeding males. This vole has brighter reddish fur on its back than the Southern Red-backed Vole. The ranges of the two species meet, in Canada, but do not overlap, suggesting that there is competition between them.